1. Field of the Invention
The present invention relates to a wire electric discharge machining system.
2. Description of the Related Art
When machining is performed continuously for a long time, or an unattended operation is performed by a wire electric discharge machine that is combined with a manipulator such as a robot which automatically changes a workpiece to be machined, a machined workpiece needs to be automatically removed that has been cut from the workpiece to be machined during machining. In the case where the cut machined workpiece drops in a machining tank and is left therein, there is the possibility that the machined workpiece interferes with a movable portion of a lower electrode in the machining tank, and is caught between the movable portion and the machining tank to damage a component in the machining tank.
As a method for automatically removing the cut machined workpiece, an apparatus is disclosed that has an arm which can move back and forth and up and down and has the wire electric discharge machine itself mounted thereon, pulls up a cut down portion by an electromagnet or an adsorption pad at an arm head, and removes the cut down portion, as is disclosed in Japanese Patent Laid-Open No. 60-180726, for instance.
In order for the apparatus in Japanese Patent Laid-Open No. 60-180726 to remove the cut machined workpiece, it is a prerequisite for the apparatus to hold the machined workpiece so that the machined workpiece does not drop from the workpiece to be machined after having been cut, but such a method as to solve the problem is not described in Japanese Patent Laid-Open No. 60-180726. However, in machined workpieces that have been cut by the wire electric discharge machine, there is a machined workpiece having such a shape as to drop into the machining tank when having been cut, and in such a case, there has been a problem that the apparatus disclosed in Japanese Patent Laid-Open No. 60-180726 cannot collect the machined workpiece.